stdbuf cannot use libstdbuf on the same directory if /proc is masked #11134
Description
$ run0 mv /usr/lib/uutils-coreutils/libstdbuf.so -t /tmp
$ cp /usr/bin/stdbuf -t /tmp
$ unshare -rm bash -c "mount -t tmpfs tmpfs /proc && /tmp/stdbuf -oL true"
stdbuf: External libstdbuf not found at configured path: /usr/lib/uutils-coreutils/libstdbuf.so
$ unshare -rm bash -c "mount -t tmpfs tmpfs /proc && /tmp/gnu-stdbuf -oL true"
# success
I believe it is because std::env::current_exe() requires /proc/self/exe:
coreutils/src/uu/stdbuf/src/stdbuf.rs
Line 189 in e939eda